You might notice the Spring Equinox shifts between March 19, 20, and 21. This happens because a "calendar year" is 365 days, but the Earth actually takes about to orbit the sun. Our leap year system mostly fixes this, but it causes the exact moment of spring to drift slightly every year.
The ground thaws enough for planting (the "last frost" date). which months are in spring
The month of transition. Expect "lion and lamb" weather, where snowstorms can quickly give way to mild, sunny afternoons. You might notice the Spring Equinox shifts between
The peak of spring. Trees are fully leafed out, the air is consistently warm, and the "spring fever" of outdoor activities is in full swing. Why Does the Date Change? the air is consistently warm